NASA eyes tomorrow's passenger planes (images)

Looking for realistic concepts, not science fiction, the aerospace agency enlists teams from from the likes of MIT and Boeing. Here's what they delivered.

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GE Aviation's 20-passenger concept

The commercial aircraft of the future are on today's drawing tables. Some of those new designs surfaced this week when NASA announced the results of its Fundamental Aeronautics Program. In the 18-month exercise, heavy-hitting industrial and academic groups contemplated specific operational, environmental, and energy efficiency goals for air travel in 2030 and beyond.

NASA says it was after realistic concepts, not science fiction. "Standing next to the airplane, you may not be able to tell the difference [from current designs], but the improvements will be revolutionary," said Richard Wahls, a project scientist at NASA's Langley Research Center in Hampton, Va., said in a statement Monday. "Technological beauty is more than skin deep."

Pictured here is a 20-passenger aircraft conceived by a team from GE Aviation; it would seat four across in an oval fuselage. The shape of the aircraft is intended to allow smooth airflow over all surfaces. Fuel cells would power electrical systems, and the racket associated with air travel would be reduced through the use of low-noise propellers and advanced engine design, as well as short takeoffs and quick climbs.

Boeing's SUGAR Volt

Boeing's team came up with several Subsonic Ultra Green Aircraft Research (SUGAR) concepts, including this one, the SUGAR Volt. The most noticeable element of the design is that the wings are long and skinny--longer from tip to tip, and shorter from leading edge to trailing edge--and as a result, truss-braced. (Given the wingspan, the wings might well have to be hinged to accommodate parking at airport terminals, Boeing said.) Under the hood of the twin-engine aircraft, Boeing envisions using a hybrid turbo-electric propulsion technology

Northrop Grumman's SELECT aircraft

From Northrop Grumman comes another clever acronym, SELECT, for Silent Efficient Low Emissions Commercial Transport. If it looks too much like the run-of-the-mill aircraft of today, not to worry, according to the company, which says the 120-passenger aircraft design would be "revolutionary in its performance, if not in its appearance."

It'll be different, Northrop Grumman says, through the use in its airframe and "ultra high bypass ratio propulsion system" construction of ceramic composites, nanotechnology, and shape memory alloys. Like the GE entry, the SELECT would help alleviate congestion at overcrowded hub airports through its ability to make use of smaller, regional airports--on runways, according to Northrop Grumman, as short as 5,000 feet.

So many potential designs

From the fanciful to the finalists--not all designs could make the cut. Here are NASA's goals for aircraft of the 2030s, as compared with those of today:

Better fuel efficiency: A greater than 70 percent reduction in fuel burn performance. That could have two salutary effects: a reduction in greenhouse gas emissions and a lower cost for air travel.

Less nitrous oxide: A greater than 75 percent reduction in nitrogen oxide emissions, per the CAEP/6 standard, which seeks to improve air quality around airports. Nitrous oxide is a key ingredient in smog.

Less noise: A 71-decibel reduction below current Federal Aviation Administration noise standards. That would make things more peaceful around airports.

Reduced congestion: "Optimal use" of runways at multiple airports in metropolitan areas, which would make for less crowded skies and ease delays.

NASA says that the concepts from the four teams were able to meet either the fuel burn or the noise goal, but not both, so it will be reassessing the overall goals to determine which need more time to get from the lab to operational use.

MIT's double-bubble design

Probably the most radical new look is the D8 "double bubble" concept from the MIT team. The group said that the 180-passenger D8 design would do the same work as the Boeing 737-800, but obviously with a wider cabin. At the rear of the aircraft are three side-by-side turbofan engines, another notable change from existing aircraft designs. Like Northrop Grumman's SELECT, the D8 would use an ultra high bypass ratio, which would mean more efficient thrust. (NASA helpfully explains: An ultra high bypass ratio means "air flow through the core of the engine is even smaller, while air flow through the duct surrounding the core is substantially larger, than in a conventional engine.")

Hybrid Wing Body H-Series

Also from the MIT research team is the Hybrid Wing Body H-Series concept, which the group says would be more akin to a Boeing 777. On paper at least, this bird is designed to carry around 350 passengers some 7,600 nautical miles on intercontinental routes--at speeds up to Mach 0.83.

For the most part, NASA says, the four teams focused on designs that would save fuel by cruising at slower speeds--roughly Mach 0.7, or 5 percent to 10 percent slower than current aircraft.

The embedded engines in the H-Series would use "variable area nozzles with thrust vectoring," and the aircraft would also feature noise-shielding technologies and advanced on-board system for monitoring vehicle health.

Lockheed Martin inverted V design

Long and needle-nosed like the Concorde supersonic transport, which flew in commercial service from the mid-1970s to 2003, this entry is from Lockheed Martin. The striking inverted-V engine-under wing configuration could dramatically lower the level of sonic booms, Lockheed says, which would allow for more flights over land. NASA is aiming eventually for a new generation of supersonic transport planes that are economically feasible but also meet strict environmental requirements.

Boeing's Icon-II

Another design for supersonic flight over land is the Icon-II, from Boeing. It would also achieve NASA's fuel burn reduction and airport noise goals, Boeing says.

NASA says that phase two of its trek toward the aircraft of 2030 began in late April when the four teams submitted additional proposals related to improving the air transportation system (better energy efficiency, lower environmental impact). The aerospace agency plans to award one or two research contracts for work starting next year.